Mozzarella cheese is a very popular cheese, in particular for pizza and salad making. Natural mozzarella cheese has a number of unique qualities which are summarized and a scientific explanation of which is given in McMahon et al., Dairy Industries International, (1999), Vol. 64, No. 7, pp. 23-26. To give an example, mozzarella cheese has unique melt characteristics and stretchability due to its oriented fibrous structure. The above features are especially important for cheese that is used in pizza production. Hence, with recent increasing popularity of pizza, the consumption of mozzarella cheese has also increased significantly.
However, natural mozzarella cheese requires an aging time of several weeks to develop the desirable melt characteristics, and has a limited shelf life. Moreover, changes in the microstructure of natural mozzarella cheese, even upon refrigerated storage, have been reported. Therefore, efforts have been made to find a cheese having the taste, the melt characteristics and the stretchability of natural mozzarella, but which need shorter production times and has a longer shelf life.
U.S. Pat. No. 5,925,398 describes a method for the production of processed mozzarella cheese that has a longer shelf life so that it can be transported without refrigeration. In this method, which does not necessitate a time and energy consuming aging step, fresh mozzarella cheese is used as the starting material, and emulsifiers are added in an amount of from 0.01 to 2.0% by weight to give a curd which is then stretched and cooked in an extruder set at a temperature of from 80 to 120° C. This process is said to afford a cheese having a functionality that is similar to aged natural mozzarella cheese.
However, processed mozzarella cheese of this kind can not be subjected to the hot filling technique in individually wrapped slices, because it looses significant amounts of water during the cooking step in the extruder and because it is too viscous for the hot filling.
Hence, processed mozzarella cheese that can be stretched like natural mozzarella, especially when heated, and which has a long shelf life while requiring only short production times, is still highly demanded. Moreover, there is a strong demand for a processed cheese of the mozzarella type having the above features that can be used in the hot filling technique to afford individually wrapped slices.